The problem of increasing the moisture permeability of leather has been recognized in the automobile industry in which leather-covered automobile seats, especially cabriolet seats, have been found to have problems resulting from the fact that the leather was not permeable to moisture. As a result of the lack of permeability to water vapor, it was not uncommon for the clothing of the user, because of restricted transpiration, to become wet. As a consequence, it has hitherto been proposed to provide leather layers with perforations, i.e. holes of a diameter of 1.5 mm and more by punching into the leather.
The punching of holes in the leather has, however, the drawback that at the edges of the stamped-out holes, leather fibers tend to protrude from the surface of the leather, through the hole and on the outer surface of the leather seat so that the appearance of the leather seat deteriorates.